Driving mechanism for components of optical system

ABSTRACT

A television camera with two camming cylinders for the focusing of its objective and for the variation of its focal length (zoom effect) has two identical driving units removably attached to its housing, each unit including an electric motor in a prismatic casing with a motor shaft and an electric connector projecting from one end of the casing. Upon emplacement of the casing on the camera housing, the motor shaft engages a transmission shaft leading through a slipping clutch to a respective camming cylinder; at the same time an electric connection is established from the motor to zooming and focusing controls on the camera or on a remote panel. The coupling of the two shafts may be effected by a spring-loaded core slidably but nonrotatably held in an axial bore of the transmission shaft, this core coacting with a complementary slot in a head of the motor shaft.

United States Patent Hess et a1.

[54] DRIVING MECHANISM FOR COMPONENTS OF OPTICAL SYSTEM [72] Inventors: Karl-Gunter Hess, Waldlaubersheim; Paul Himmelshach, Bosgrunderweg 65; Otto Thomas, Matthias-Grunewald-Str. 36, both of Bad Kreuznach, all of Germany [51] Int. Cl ..G03b 3/00, G03b 19/18, G03 b 21/32 [58] Field of Search ..355/55, 58; 95/45, 58;

[56] References Cited UNITED STATES PATENTS 3,272,106 9/1966 Czekalla ..95/58 [15] 3,682,072 1 Aug. 8, 1972 2,912,898 11/1959 Oxberry ..352/138 Primary Examiner-Joseph F. Peters Assistant Examiner-Richard A. Wintercorn Attorney-Karl F. Ross ABSTRACT A television camera with two camming cylinders for the focusing of its objective and for the variation of its focal length (zoom effect) has two identical driving units removably attached .to its housing, each unit including an electric motor in a prismatic casing with a motor shaft and an electric connector projecting from one end of the casing. Upon emplacement of the easing on the camera housing, the motor shaft engages a transmission shaft leading through a slipping clutch to a respective camming cylinder; at the same time an electric connection is established from the motor to zooming and focusing controls on the camera or on a remote panel. The coupling of the two shafts may be effected by a spring-loaded core slidably but nonrotatably held in an axial bore of the transmission shaft, this core coacting with a complementary slot in a head of the motor shaft.

8 Claims, 7 Drawing Figures PATENTEIJnu's 8 m2 3.682.072

Karl-GUnfer Hess Paul Himmelsbach 0H0 Thomas INVENTOR.

ATTORNEY P'A'IENTEmuc' 8 m2 SLIPPING CLUTCH SHEEI 2 0F 3 T0 CONTROL '1 PANEL Karl-Giinfer Hess Paul Himmelsbach Offo Thomas INVENTOR.

ATTORNEY PAIEml-fmuc 8 m2 3,682,072 sum 3 Hi3 Fl 7 Karl- GUnfer Hess Paul Him melsbach 0H0 Thomas INVENTORS.

AIIOIBGY DRIVING MECHANISM FOR COMPONENTS OF OPTICAL SYSTEM This application is a continuation-in-part of our copending application, Ser. No. 602 filed 5 Jan. 1970.

Our present invention relates to an assembly for controlling the operation of an optical system, such as that of a photographic, cinematographic or television camera, to vary its focal length (zoom effect), to focus it, to adjust its diaphragm, or to perform some other recurrent function such as the changing of front attachments or (in a projector) the feeding of slides.

It is known, e.g. from commonly owned US. Pat. No. 3,165,044 in the name of Paul Himmelsbach, to provide a reversible electric motor in a camera for the axial displacement of one or more objective components in response to closure of a manual switch on the camera housing. In the case of an 8-mm'movie camera, for example, the motor may be energized-by one or more batteries accommodated in the camera housing. With larger equipment, such as a television camera, the power supply may have to be separated from the drive unit and may include a portable battery pack or a cable to be plugged into a utility outlet.

Since the electric driving unit and its coupling with the movable actuating means of the optical system occasionally require inspection, repair or replacement, it is inconvenient to make this unit a fixed part of the enclosure for the optical system. If the driving unit is detachable, on the other hand, its connection to the power supply creates problems.

It is, therefore, the principal object of our present invention to provide an assembly of this general type wherein a detachable driving unit, upon being emplaced on an objective housing, is instantly connected to its power supply (which may be mounted on the housing or separate therefrom) and is simultaneously coupled with the actuating means inside the housing, such as a rotatable cam for the axial displacement of a lens member.

A more specific object is to provide an assembly of this type wherein two related but independent operations, such as focusing and zooming, are carried out by two identical and interchangeable driving units whereby, upon failure of one unit, the other may be used to perform the more essential operation (e.g. focusing) and whereby, furthermore, an identical standby unit may be used as a replacement for either of the two operating units.

A further specific object is to provide simple and effective means for automatically establishing a driving connection between two previously uncoupled shafts upon an operative juxtapositioning thereof, with one of these shafts set in rotation by a drive motor.

These objects are realized, pursuant to our present invention, by the provision of at least one and preferably two detachable drive units each with a preferably prismatic casing containing an electric motor whose output shaft projects from the casing, preferably at an end face of the prism, the energizing circuit for the motor including a pair of mating electrical connectors on the casing and on the objective housing, such as a plug and a jack, interfitting upon emplacement of the casing on the objective housing. Such emplacement, moreover, operatively couples the output shaft of the motor with a confronting input shaft on the housing, the latter shaft being linked with the controlled actuating means (e.g. a camming cylinder) through suitable transmission means advantageously including a slipping clutch. Owing to the presence of such a clutch, the motor can remain energized for rotation in one sense even after the displaceable objective component has arrived in a limiting position at one end of its range, a subsequent reversal of the sense of rotation then displacing the component in the opposite direction until the other end of the range is reached. In this way, proper correlation between the movement of the component and the operation of a reversing switch on a control panel remote from the housing, or on the housing itself, can be achieved regardless of the original position of the controlled element upon the coupling of its input shaft with the motor shaft of the associated driving unit.

To effect such coupling, one of the two coacting shafts preferably the motor shaft can be axially shiftable and resiliently biased to snap into an entrainment position, with interengagement of mating formations such as a rib and a slot on the confronting shaft ends, upon attainment of a predetermined relative angular position of the two shafts.

According to a more advantageous embodiment, which greatly reducesthe axial stress upon the shaft forming the active part of the coupling, one of the two shafts carries an axially shiftable but relatively nonrotatable coupling element engageable with a complementa'ry formation on the other shaft in the predetermined angular position of these shafts, the coupling element being urged toward such engagement by a loading spring or other (e.g. electromagnetic or fluid-pressureresponsive) biasing means.

The driving unit may also include sensing means for signaling the instant position of the controlled and/or its rate of displacement to an indicator on the control panel or the housing. The data thus transmitted may be used at the control station, for example, to effect automatic reversal of a zoom drive upon arrival in eitherlimiting position, as is well known per se.

The above and other features of our invention will be described in greater detail hereinafter with reference to the accompanying drawing in which:

FIG. 1 is a somewhat diagrammatic illustration of a varifocal objective of a television camera equipped with a pair of detachable driving units according to our invention;

FIG. 2 is a cross-sectional view taken on the line ll II of FIG. 1;

FIG. 3 is an isometric view of a driving unit forming part of the assembly of FIGS. 1 and 2;

FIG. 4 is a fragmentary sectional view of part of the assembly of FIGS. 1 and 2 with a driving unit thereof in the process of emplacement;

FIG. 5 is an axial sectional view of a shaft coupling for an assembly similar to that of the preceding Figures, shown in an engaged position;

FIG. 6 is a partly sectional view of the coupling of camera housing 1 also partly illustrated in FIG. 4.

Housing 1 has a front opening 16 in line with the optical axis here shown to comprise three axially movable lens members 2, 3 and 4 (together with other components not illustrated). Front lens 2, held in a mount 17 which is slidable on a pair of parallel rods l8, 19, is controlled by a camrning cylinder 6 with a helical groove engaging a follower 20 secured to lens mount 17. Another camming cylinder 7 has a helicoidal groove engaging two followers 21, 22 rigid with similarly guided lens mounts 23, 24 of lenses 3 and 4, respectively, to impart differential motion to these two lenses.

The housing 1 is formed at its rear with a pair of sockets 25, 25' accommodating respective driving units 8, 8' with prismatic casings 9, 9. The two driving units are identical and, as illustrated in FIGS. 3 and 4 for unit 8, comprise each a reversible electric motor 26 with a shaft 27 onto which an output shaft 12 is slidably' splined under outward axial pressure from a spring 28. The free end of shaft 12, projecting from casing 8, has a transverse slot 13 to receive a complementary rib 29 on the confronting end of an input shaft30 of a transmission serving to couple the cylinder 6 with motor 26 for entrainment thereby; this transmission further includes a slipping clutch on shaft 30 and a belt drive.3l lead ing from the driven element of that clutch to the cylinder shaft. Corresponding elements fonning part of unit 8' or associated therewith have been designated by the same reference numerals supplemented by prime marks. Casing 9 further contains a sensor 32 connected to the energizing circuit of motor 26, this circuit including a cable 33 which terminates at a plug projecting from one of the end faces of the casing next to shaft 12. Plug 10 mates with a jack 11 on housing 1 whence an extension cable 34 leads to a control panel not shown.

Housing 1 is formed, along one of the rectangular surfaces defining the prismatic socket 25, with a slot 35 adapted to receive a bayonet lug 14 on casing 9 whereby the casing may be emplaced in its socket by transverse and longitudinal motion (arrows A and B in FIG. 4) to introduce the lug 14 into slot 35 while engaging plug 10 and shaft 12 with jack 11 and shaft 30, respectively. The anchoring of the casing 9 to housing 1 may be secured by a latch 15 swung out to overhang the rear face of the casing as shown in FIG. 1. I

In most instances, the slot 13 will not be precisely aligned with the rib 29 upon the emplacement of unit 8. In such a case, the shaft 12 is repressed by the shaft 30 against the force of spring 28 until, upon the ensuing rotation of shaft 27 by motor 26, the formations 13 and 29 register with each other whereupon shaft 12 advances toward shaft 30 to complete the driving connection. In this position of interengagement, the lens 2 may find itself anywhere within its range of displacement; upon a certain amount of rotation of cylinder 6, the lens will come to rest against an abutment defining one of the limits of its stroke so that the clutch 5 will slip as the shaft 30 continues to turn. This condition may be reported to the control panel by the sensor 32 responding, for example, to the increase in current drawn by the motor in working against the drag of the clutch. At the control panel, therefore, a lamp may light and/or a switch connecting the cable 34 to its power source may be tripped for the manual or automatic reversal of the operation of motor 26. At the opposite end of the range, another reversal may take place in like manner,

the lens 2 thus reciprocating until the motor circuit is broken. A visual indicator, not shown, may be provided on the casing 9 or on the control panel to displace a needle across a scale in step with the load represented by lens 2, as by actuating a relay upon each current reversal to complete an integrating circuit for the progressive energization of a deflecting coil or the like to move the needle in one or the other direction at a rate commensurate with motor speed. Naturally, a position indicator mechanically coupled with lens mount 17 or with camming. cylinder 6 could be provided within housing 1 and could be viewed through a window as is well known per se.

Even though the two units 8 and 8 are identical, their motors may be operated at different speeds by means of suitably proportioned impedance networks included in their respective energizing circuits at the control panel. Thus, it will be immaterial whether these units are inserted so that unit 8 drives the cylinder 6 while unit 8' drives the cylinder 7, as illustrated, or whether they are interchanged. By the same token, any standby unit of like construction may be substituted for either of these two units.

As illustrated in FIG. 2, a rigid strap 36 may be detachably secured to these units to interconnect them for joint emplacement and removal. Upon removal of these units, the exposed ends of input shafts 30 and 30' could be coupled to conventional manual or automatic drives remote from housing 1, e.g. with the aid of flexible shafts.

In the case of smaller cameras, the power supply for the drive motor 26 could also be disposed (in the form of one or more batteries) within the casing 9 or 9'.

FIGS. 5 7 we have shown a shaft coupling for operatively interconnecting the clutch 5 and the motor 26 in a manner dispensing with the need for axial mobility of either of their shafts. The clutch shaft, here designated 130, is formed for this purpose with an axial bore 43 open toward the motor shaft 112 aligned therewith, this bore accommodating an axially slidable core 40 as well as a biasing spring 128 urging it toward a head 44 rigid with shaft 112. A lug 41 on core 40 slides in an axially extending slot 42 of shaft to prevent the core from rotating with reference to that shaft. Head 44 has a transverse recess 113 fitting a prismatic key 129 on the projecting end of core 129.

In the engaged position shown in FIG. 5, key 129 is received in recess 113 so that shafts 112 and 130 are positively coupled for joint rotation. FIG. 6 shows a disengaged position in which the key 113 lies skew to the recess 113 toward which it is ineffectually urged by the spring 128. FIG. 7 illustrates a position in which the key 129 has almost aligned itself with recess 113 so that a slight further rotation of motor shaft 112 (in a counterclockwise direction as seen on looking toward shaft 130) completes the connection.

Core 40 and bore 43 could, of course, also be given complementary noncircular cross-sections instead of being cylindrical as shown, thereby dispensing with the need for detent means 41, 42.

a casing detachably secured to said housing; an input shaft in said housing confronting said casing; an electric motor in said casing provided with an output shaft coaxially confronting said input shaft;

transmission means in said housing linking said input shaft with said actuating means;

an axially shiftable coupling element on one of said shafts, the other of said shafts being provided with a complementary formation engageable by said coupling element in a predetermined relative position of said shafts for establishing a driving connection therebetween; i

i and biasing means for shifting said coupling element into engagement with said formation in said relative position.

2. The combination as defined in claim 1 wherein said housing and said casing are provided with complementary electric connectors coacting to establish an energizing circuit for said motor upon emplacement of said casing, said energizing circuit including control means for said motor remote from said casing.

3. The combination as defined in claim 1 wherein 6 said biasing means comprises a spring bearing axially upon said coupling element.

4. The combination as defined in claim 3 wherein said one of said shafts is provided with an axial bore receiving said spring and said coupling element, said bore being open toward said other of said shafts.

5. The combination as defined in claim 4 wherein said coupling element is a cylindrical core with a profiled extremity and with detent means preventing rotation of said core, said complementary formation being a profiled recess in an end of said other of said shafts facing said extremity.

6. The combination as defined in claim 5 wherein said detent means comprises a radial lug on said core, said one of said shafts having an axially extending slot opening into said bore and accommodating said lug.

7. The combination as defined in claim 1 wherein said one of said shafts is said input shaft.

8. The combination as defined in claim 1 wherein saidtransmission means includes a slipping clutch. 

1. In an optical system, in combination: an objective housing; a displaceable objective component in said housing; movable actuating means for said component in said housing; a casing detachably secured to said housing; an input shaft in said housing confronting said casing; an electric motor in said casing provided with an output shaft coaxially confronting said input shaft; transmission means in said housing linking said input shaft with said actuating means; an axially shiftable coupling element on one of said shafts, the other of said shafts being provided with a complementary formation engageable by said coupling element in a predetermined relative position of said shafts for establishing a driving connection therebetween; and biasing means for shifting said coupling element into engagement with said formation in said relative position.
 2. The combination as defined in claim 1 wherein said housing and said casing are provided with complementary electric connectors coacting to establish an energizing circuit for said motor upon emplacement of said casing, said energizing circuit including control means for said motor remote from said casing.
 3. The combination aS defined in claim 1 wherein said biasing means comprises a spring bearing axially upon said coupling element.
 4. The combination as defined in claim 3 wherein said one of said shafts is provided with an axial bore receiving said spring and said coupling element, said bore being open toward said other of said shafts.
 5. The combination as defined in claim 4 wherein said coupling element is a cylindrical core with a profiled extremity and with detent means preventing rotation of said core, said complementary formation being a profiled recess in an end of said other of said shafts facing said extremity.
 6. The combination as defined in claim 5 wherein said detent means comprises a radial lug on said core, said one of said shafts having an axially extending slot opening into said bore and accommodating said lug.
 7. The combination as defined in claim 1 wherein said one of said shafts is said input shaft.
 8. The combination as defined in claim 1 wherein said transmission means includes a slipping clutch. 